The segment of our research supported by this grant will be devoted to a study of the growth of individual animal and human cells in the laboratory. This study will focus on the effect of various hormones, drugs and other chemicals on cell growth and proliferation. A particular goal will be to develop a system for rapid, reliable, inexpensive testing of certain food additives, environmental chemicals and other environmental agents which might disturb cell growth in such a way as to cause mutations, cancer or birth defects. In addition to these immediate goals related to medical problems, we will also study control of cell division and growth during normal, orderly biological processes.